well for me...base on the originality of the story...i have 2 say that hkt is better...majority of the scenes in the hkt was almost the same as the manga...
but base on the looks and personality of the characters...and also the way the story flows...ihave 2 go to hkj...it was totally hilarious...

actually...it is hard 2 compare them because for a fact...both are totally different...hkt is more on the romantic story of mizuki and sano...hkj is more on the friendship between the students in the school...hehehehe...

by the way...i hate GMA for cutting to much scenes in the hkj...the essence of the story was totally destroyed!! hmpf!!

I have to say i like the japanese version wayyyy better not only because toma ikuta and ogui shun were in it it was just that the way the japanese version ended made sense as apposed to the Taiwanese version hkt left you with alot of questions like did they ever find out how they feel about each other and if sano is going to tell her that he knows that she is a guy I mean hkt was good some parts were really good but all in all hkj was better (sorry if i wrote a novel just saying how i felt about it)

Hmm for me eventhough i prefer Japan version one, but the Taiwan is quite romantic and Wuchun as Sano is really similar to Sano in manga. While Sano in Japan version is too cold and uncaring, and Nakatsu seems to play role more important than Sano. But you know nothing can compare Toma as Nakatsu. His acting was hillarious and awesome. So i would say GO JAPAN VERSION :). I love this show very funny and unusual hehe.

Can I say the manga?
They're both good in their own ways. I like Japan better, but that's just me.
Taiwan's version follows the manga more (and has WU CHUN and Jiro).
The Japanese version has a much better ending and I DON"T HAVE TO FIGURE OUT NEW NAMES! (the manga and japan version have the same names, taiwan changed them).